BAGHDAD, Iraq — Iraqi leaders have failed to take advantage of a reduction in violence to make adequate progress toward resolving their political differences, Gen. David Petraeus, the top U.S. commander in Iraq, said Thursday.

Petraeus, who is preparing to testify to Congress next month on the Iraq war, said in an interview that “no one” in the U.S. and Iraqi governments “feels that there has been sufficient progress by any means in the area of national reconciliation,” or in the provision of basic public services.

The general’s comments appeared to be his sternest to date on Iraqis’ failure to achieve political reconciliation. In February, following the passage of laws on the budget, an amnesty for certain detainees, and provincial elections, Petraeus was more encouraging. “The passage of the three laws today showed that the Iraqi leaders are now taking advantage of the opportunity that coalition and Iraqi troopers fought so hard to provide,” he said at the time.

Petraeus came to Iraq a year ago to implement a counterinsurgency strategy, backed up by a temporary increase of about 30,000 U.S. troops, intended to ease the sectarian and political differences that threaten to break the country apart.

The Shiite-led government of Prime Minister Nouri Maliki has won passage of some legislation that aids the cause of reconciliation, drawing praise from President Bush and his supporters. But the Iraqi government also has deferred some of its most important legislative goals, including laws governing the exploitation of Iraq’s oil resources, that the Bush administration had identified as necessary benchmarks of progress toward reconciliation.

Many Iraqi parliament members and other officials acknowledge that the country’s political system is often paralyzed by sectarian divisions, but they also say that American expectations are driven by considerations in Washington and do not reflect the complexity of Iraq’s problems.

In what appeared to be a foreshadowing of his congressional testimony, which his aides said he would not discuss explicitly, Petraeus insisted that Iraqi leaders still have an opportunity to act. “We’re going to fight like the dickens” to maintain the gains in security and “where we can, to try and build on it,” he said.

While violence has declined dramatically since late 2006, when thousands of Iraqis were being killed every month, U.S. military data show that attacks on U.S. troops and Iraqi civilians have leveled off or risen slightly in the early part of 2008. “I don’t see an enormous uptick projected right now,” Petraeus said, speaking in his windowless office in the U.S. Embassy, which is housed in Saddam Hussein’s former Republican Palace. “What you have seen is some sensational attacks, there’s no question about that.”

Petraeus said that several factors may account for the recent violence, including increased U.S. and Iraqi operations against insurgents in the northern city of Mosul — which has lately become one of Iraq’s most dangerous — and insurgent efforts to re-establish some of their Baghdad safe havens. Petraeus said that U.S. commanders could not discount the possibility that insurgents “know the April testimony is coming up.”

The additional forces sent to Iraq last year have begun to depart, and they will be gone by mid-summer, leaving in place a baseline U.S. presence of about 130,000 troops. Petraeus said it would increasingly fall to Iraqi security forces and neighborhood patrols funded by the United States to help keep violence down.

Petraeus also said the U.S. government would temporarily freeze further reductions in the American troop presence to allow for a “period of consolidation and evaluation after reducing our ground combat forces by over a quarter.” He said he would discuss the length and timing of what the military terms an “operational pause” during his testimony.